OP solved it, closing

There are Sample Tests you can run your code with before clicking ATTEMPT. When you do, there are additional tests, and also random tests. So, your code needs to be correct for all of them. In the case of your error message, you returned an array of length 52, whereas that particular test required an empty array.

Make sure that you're testing the same thing, the thing that failed - otherwise there's no point to it. It's very common around here to say "works locally but not here" and from what I can tell it's almost always caused by not measuring the same thing, making the comparison meaningless.
If you're unable to reproduce it locally, then you can still debug it here where you can repreduce it.